EP0336686B1 - Filtre à substance filtrante granulaire - Google Patents

Filtre à substance filtrante granulaire Download PDF

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Publication number
EP0336686B1
EP0336686B1 EP89303281A EP89303281A EP0336686B1 EP 0336686 B1 EP0336686 B1 EP 0336686B1 EP 89303281 A EP89303281 A EP 89303281A EP 89303281 A EP89303281 A EP 89303281A EP 0336686 B1 EP0336686 B1 EP 0336686B1
Authority
EP
European Patent Office
Prior art keywords
air
water
conduit
duct
apertures
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP89303281A
Other languages
German (de)
English (en)
Other versions
EP0336686A1 (fr
Inventor
Philip Antony Weston
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PWT Projects Ltd
Original Assignee
PWT Projects Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PWT Projects Ltd filed Critical PWT Projects Ltd
Priority to AT89303281T priority Critical patent/ATE84239T1/de
Publication of EP0336686A1 publication Critical patent/EP0336686A1/fr
Application granted granted Critical
Publication of EP0336686B1 publication Critical patent/EP0336686B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
    • B01D24/20—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being provided in an open container
    • B01D24/24—Downward filtration, the container having distribution or collection headers or pervious conduits
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46—Regenerating the filtering material in the filter
    • B01D24/4626—Construction of spray heads specially adapted for regeneration of the filter material or for filtrate discharging
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
    • B01D24/46—Regenerating the filtering material in the filter
    • B01D24/4631—Counter-current flushing, e.g. by air
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S55/00—Gas separation
    • Y10S55/32—Gaseous fluid conveying

Definitions

  • This invention relates to granular media filters and to an improved system of air scouring and water backwashing.
  • the invention relates to the use of special conduit for the air and water.
  • Granular media filters are commonly provided with an underdrain system comprising perforated lateral pipes connected to a header pipe or duct. Large filters constructed in concrete are provided with an extensive array of such lateral pipes. The function of the underdrain system is to collect the filtrate and, more importantly, to distribute the backwash water used for cleaning.
  • GB-A-2 002 251 discloses a multi-channelled duct having a first central passageway and, on either side of the passageway, second and third passageways communicating with the passageway via apertures.
  • the passageways communicate with the exterior via openings.
  • the ducts are laid in an array in the lower zone of a filter basin beneath a gravel layer and layer of filter material.
  • dirty water or the like is passed through the layers and collected in the passageways from where it flows to a conduit.
  • water is supplied to the passageway and flows from there through the openings and through the apertures and openings.
  • GB-A-304 967 discloses a two-duct pipe in which a lower duct, for water, is connected to the top of the pipe via an internal venturi tube passing through a superimposed upper duct for air. Air is drawn into the venturi by the water flowing and mixes therewith. This type of system is obviously difficult to adjust, since the air-water ratio obtained depends on each venturi. The system could not, therefore, be built into the floor of a filter.
  • German Patent DE-C-736915 discloses a two-duct pipe, the two ducts separated by an internal wall. Each duct has an external wall in common, the external wall being provided with axially spaced apertures for emission of water or air. This arrangement enables water or air to be emitted when supplied individually. However, this system does not provide an effective simultaneous flow of air and water.
  • An alternative system for a combined air and water wash is to employ two separate distribution systems which are dedicated respectively to air and to water. This is a reliable and robust solution to the problem, but it involves the additional costs of the extra materials, the supports and the erection labour.
  • a granular media filter including an underdrain system comprising perforated lateral conduits arranged for the distribution of air and water either separately or concurrently for scouring and backwashing of the filter, each conduit being in the form of a single linear conduit containing two or more separate axially parallel ducts separated by one or more internal wall(s), each duct having an external wall in common with the conduit, said external wall is provided with axially spaced apertures for emission of water or air, at least one duct being arranged in each conduit for the distribution of air and at least one duct is arranged for the distribution of water, there being no intercommunication for water or air between the ducts, characterised in that separate apertures are provided for air and for water and that either (a) the external wall of the duct for air distribution is provided with at least one additional aperture at a lower level than the said axially spaced apertures or (b) axially spaced apertures are in at least one of the ducts for air distribution located in an upper position and projected downwards
  • the conduit comprises two ducts running side by side or one on top of the other with a common dividing wall between them.
  • the apertures can comprise simple bored holes or more elaborate nozzles or jets.
  • the apertures may be provided with strainer means, although it is important that when strainer means are present, the main point of pressure loss in the water or air should be at the point of emergence from the duct and not from the strainer into the filter medium.
  • each duct wall will be suitably spaced depending on the degree of backwash and sparging required. Apertures for water may be at different spacings than apertures for air, or alternatively the apertures may be grouped in pairs if water and air are required at the same point. Similarly, the size of the apertures will vary, and in general apertures for air will be of smaller diameter than apertures for water.
  • the conduit is conveniently extruded in a one piece form, for example by extrusion moulding of a suitable plastic, such as uPVC, ABS etc.
  • a suitable plastic such as uPVC, ABS etc.
  • metal extrusions can be considered.
  • Other methods of manufacture are obviously available, including folding and welding of metal sheet.
  • extruded plastic is most preferred, for its ease of manufacture and its lightness.
  • the cross-section of the conduit may be any convenient shape, depending on the layout of the filter and the direction from which air and water are provided.
  • the conduit is of round or rectangular section.
  • the conduit is of generally round section, and contains two superimposed ducts of generally semicircular section separated by a horizontal dividing wall or septum.
  • the apertures are located on the top and bottom of the conduit (i.e. on an axis perpendicular to the septum).
  • one or two or more secondary apertures are provided in the air duct at a lower level than the previously mentioned axially spaced apertures so that the water which fills the duct whilst out of action may be substantially emptied from it when the air is applied and that the residual water level is taken well below the service orifices.
  • said axially spaced apertures are located in an upper position on at least one of the ducts for air distribution and each of said apertures is projected downwards into the duct as an inwardly extending duct.
  • the underdrain system for a granular media filter comprises a horizontal array of conduits located at the bottom of the filter medium and arranged to receive and distribute supplies of water and air.
  • the conduit has a cross section as shown in Figure 1 comprising a generally circular pipe 1 provided with a horizontal internal wall 2 dividing the pipe into two superimposed ducts 3, 4. Apertures 5, 6 are provided along the top and bottom of the pipe 1.
  • FIG. 2 A typical arrangement shown, in part, in Figure 2 where the conduit 1 is disposed at the bottom of granular filter media 7 in a concrete enclosure 8.
  • the upper duct 3 is connected to an air supply duct 9, arranged for supply of compressed air at an appropriate pressure.
  • a water manifold connects with the lower duct 4 for the provision of water or, in reverse, for removal of filtrate.
  • the conduit 1 merely rests at the bottom of the closure 8, generally surrounded by the filter medium.
  • the apertures 5, 6 can conveniently be surrounded by a collar 11 fitted with a mesh or perforated sheet 12, together comprising strainer means for preventing suspended particles from entering the ducts during filtration.
  • auxiliary aperture or apertures (13) near the base of the air duct. If the pressure across the service apertures (5) is greater than the head of water between the service apertures and the secondary aperture then the secondary aperture will start to discharge air after the water level has stabilised. It is of course preferable that only one secondary aperture be employed, otherwise there may be uncertainty so to whether both discharge when the latter stage is reached.
  • FIG. 5 illustrates such an arrangement.
  • the dividing wall (2) is vertical and air and water apertures (5, 6) are both at the top and open into a distribution collar (11).
  • the configuration facilitates casting in of infill concrete (15) to provide a hygenic filter floor on which there are no zones of media below the strainers which do not receive the combined or separate air scour.
  • Such a floor therefore provides an upper surface identical to that of a suspended concrete floor, without the cost and depth of the normal underfloor plenum chamber.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)
  • Filtering Of Dispersed Particles In Gases (AREA)
  • Centrifugal Separators (AREA)
  • Disintegrating Or Milling (AREA)
  • Filtering Materials (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)

Claims (8)

  1. Un filtre à substance filtrante granulaire englobant un système de drainage souterrain comprenant des conduits latéraux perforés (1) agencés en vue de la distribution d'air et d'eau, ou bien séparément ou bien conjointement, pour le rinçage et le lavage à contre-courant du filtre, chaque conduit (1) ayant la forme d'un conduit linéaire unique contenant deux ou plusieurs tuyaux séparés axialement parallèles (3, 4) séparés par une ou plusieurs parois internes (2), chaque tuyau (3, 4) ayant une paroi externe en commun avec le conduit, ladite paroi externe comportant des ouvertures espacées axialement (5, 6) en vue de l'émission d'eau ou d'air, au moins un tuyau (3, 4) étant agencé dans chaque conduit pour la distribution d'air et au moins un tuyau (3, 4) étant agencé pour la distribution d'eau, aucune intercommunication pour l'eau ou l'air n'existant entre les tuyaux (3, 4), caractérisé en ce que des ouvertures séparées (5, 6) sont prévues pour l'air et l'eau et en ce que ou bien (a) la paroi externe du tuyau pour la distribution d'air comporte au moins une ouverture supplémentaire (13) à un niveau plus bas que lesdites ouvertures espacées axialement (5, 6) ou bien (b) les ouvertures espacées axialement (5, 6) sont agencées, dans au moins un des tuyaux servant à la distribution de l'air, dans une position plus élevée et orientées vers le bas dans le tuyau sous forme de tuyaux s'étendant vers l'intérieur (14).
  2. Un filtre selon la revendication 1, dans lequel le conduit est formé par extrusion d'une seule pièce.
  3. Un filtre selon les revendications 1 ou 2, ayant un conduit de section généralement circulaire.
  4. Un filtre selon l'une quelconque des revendications 1 à 3, dans lequel les deux ou plusieurs tuyaux séparés sont agencés côte à côte, la (les) paroi(s) interne(s) étant pratiquement verticale(s).
  5. Un filtre selon la revendication 4, dans lequel la surface supérieure du conduit comporte des manchons d'alimentation (11) s'étendant vers le haut, les ouvertures s'ouvrant vers lesdits manchons (11) de sorte que chaque manchon (11) peut communiquer avec lesdits deux ou plusieurs tuyaux et recevoir ainsi de l'air et de l'eau.
  6. Un filtre selon la revendication 5, dans lequel le système de drainage souterrain est encastré dans du béton pour former un fond du filtre à partir duquel les manchons d'alimentation (11) peuvent s'élever.
  7. Un filtre selon l'une quelconque des revendications 1 à 6, dans lequel les ouvertures et/ou les manchons comportent un moyen de crépine (12).
  8. Un procédé pour équiper un filtre à substance filtrante granulaire d'un rinçage à l'air et d'un lavage à contre-courant à l'eau combinés par incorporation et utilisation d'un système de drainage souterrain comme défini dans l'une quelconque des revendications 1 à 7.
EP89303281A 1988-04-07 1989-04-03 Filtre à substance filtrante granulaire Expired - Lifetime EP0336686B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89303281T ATE84239T1 (de) 1988-04-07 1989-04-03 Filter mit koernigem filtermaterial.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888808133A GB8808133D0 (en) 1988-04-07 1988-04-07 Granular media filters
GB8808133 1988-04-07

Publications (2)

Publication Number Publication Date
EP0336686A1 EP0336686A1 (fr) 1989-10-11
EP0336686B1 true EP0336686B1 (fr) 1993-01-07

Family

ID=10634721

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89303281A Expired - Lifetime EP0336686B1 (fr) 1988-04-07 1989-04-03 Filtre à substance filtrante granulaire

Country Status (6)

Country Link
US (1) US4995990A (fr)
EP (1) EP0336686B1 (fr)
AT (1) ATE84239T1 (fr)
DE (1) DE68904222T2 (fr)
GB (1) GB8808133D0 (fr)
NZ (1) NZ228643A (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5269920A (en) * 1991-04-03 1993-12-14 The F. B. Leopold Co., Inc. Cap system for underdrains in gravity filters
US5089147A (en) * 1991-05-01 1992-02-18 Zimpro Passavant Environmental Systems, Inc. Underdrain for granular medium filter
JPH06170117A (ja) * 1992-08-05 1994-06-21 Peter J Neuspiel 濾過装置用下部集水モジュール及び濾過装置用下部集水システム
US5489388A (en) * 1994-04-12 1996-02-06 The F. B. Leopold Co., Inc. Apparatus and method for improving gas backwash in lateral underdrains
US6312611B1 (en) 1996-07-31 2001-11-06 The F.B. Leopold Co., Inc. Apparatus for distributing gas and liquid during concurrent gas/liquid backwash in filter underdrain flumes
BRPI0612927A2 (pt) * 2005-05-17 2012-10-02 Leopold Co Inc F B aparelho e método para a distribuição de gás e de lìquido durante a contra-lavagem nos filtros das calhas inferiores de escoamento usando uma separação dupla
US20080121580A1 (en) * 2006-11-27 2008-05-29 Weatherford/ Lamb, Inc. Geometrically Variable Filter Underdrain Header
US10022654B2 (en) 2012-12-17 2018-07-17 Xylem Water Solutions Zelienople Llc Gas-liquid distribution technique for water or wastewater filters using underdrains

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1069737A (en) * 1911-03-13 1913-08-12 William A Stevenson Method of cleaning filter-beds.
GB304967A (en) * 1928-02-20 1929-01-31 Bamag Meguin Ag Improvements relating to filters
DE689443C (de) * 1935-09-18 1940-03-20 Max Kolshorn uer Fluessigkeiten
DE736915C (de) * 1936-11-28 1943-07-01 Bamag Meguin Ag Rueckspuelfilterboden fuer koernige Filtermasse
US2767852A (en) * 1952-05-13 1956-10-23 Ellila Karl Lauri Filter apparatus
FR1470610A (fr) * 1966-03-03 1967-02-24 Beteiligungs & Patentverw Gmbh Fond pour filtre à liquide
US3954620A (en) * 1974-10-25 1976-05-04 Hydrotechnic Corporation Filtration and backwashing apparatus for use with a water filtration system
JPS5635219Y2 (fr) * 1977-08-12 1981-08-19
US4707257A (en) * 1986-05-29 1987-11-17 The Graver Company Air/water distributor underdrain
US4753726A (en) * 1987-03-09 1988-06-28 Essef Corporation Distributor for filters

Also Published As

Publication number Publication date
NZ228643A (en) 1990-06-26
ATE84239T1 (de) 1993-01-15
DE68904222T2 (de) 1993-07-01
DE68904222D1 (de) 1993-02-18
US4995990A (en) 1991-02-26
GB8808133D0 (en) 1988-05-11
EP0336686A1 (fr) 1989-10-11

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